Wearables and injury prevention: the pitfalls and opportunities for monitoring musculoskeletal loading

In scientific studies and in commercial wearable devices it is often assumed that increases in ground reaction forces (GRF), or in GRF-correlated signals from pressure-sensing insoles and inertial measurement units (IMUs), indicates increases in musculoskeletal loading or overuse injury risk (e.g., bone stress fracture risk). Here we summarize our recent empirical findings on tibia stress fracture risk and running that demonstrate that this common assumption is flawed. Specifically, we show that GRF metrics are not strongly correlated with tibial bone forces across a range of running speeds and slopes. Next, we outline a new approach: using data from multiple wearable sensors on the foot and shank and a musculoskeletal model to better estimate loading on the tibia bone. Our preliminary feasibility assessment indicates this multi-sensor data fusion approach can outperform conventional GRF metrics, offering a promising solution for monitoring musculoskeletal forces unobtrusively in daily life.